Battle of Cer

The Battle of Cer was fought from 15 to 24 August 1914 during the Serbian campaign of World War I. The Austro-Hungarian Army, commanded by Oskar Potiorek, invaded Serbia and attempted to avenge the assassination of Archduke Franz Ferdinand by dealing the Serbs a decisive defeat, only to be defeated at Cer Mountain after heavy fighting.

Background
In August 1914, Austria-Hungary found itself at war with Serbia and Russia, a two-front conflict for which it was ill-prepared. Austria-Hungary triggered World War I with its declaration of war on Serbia on 28 July 1914, provoking Russian mobilization in support of the Serbs. Austro-Hungarian Chief of Staff Conrad von Hotzendorf's priority was to defeat Serbia, but he was under pressure to mount an offensive against Russia.

Also committed to splitting their forces between two fronts, the Russians intended to invade Germany through East Prussia, while also attacking Austria-Hungary's eastern province of Galicia.

Campaign
The mobilization of the Austro-Hungarian armies was plagued by indecision about whether their initial target should be Russia or Serbia. Prewar planning had given Austro-Hungarian Chief of Staff Conrad von Hotzendorf the Second Army to send against either the Serbs or Russians. At the outbreak of war, he ordered it to Serbia, but then realized he needed to use it against the mobilizing Russians. The Second Army went to the Serbian front, stayed for three weeks, and then went by train to Austria-Hungary's eastern province of Galicia. It played no part in the opening battles on either front.

Invasion
Austria-Hungary expected an easy victory against Serbia, but its divided forces left inadequate strength to overcome a country that had mobilized most of its male population. The Serbs were commanded by Field Marshal Radomir Putnik, who had been allowed to return to Serbia from an Austrian spa when war broke out. The Austro-Hungarian invasion was entrusted to Oskar Potiorek, governor of Bosnia, who had ridden in Franz Ferdinand's car on the day of the Sarajevo assassination. He was fiercely committed to punishing the Serbs, giving his troops license to kill civilians and destroy property.

Potiorek's plans proceeded woefully, however. Crossing the Drina and Sava Rivers, his forces advanced only as far as Putnik's defensive line. After heavy fighting, they were thrown back, and by 24 August the attack against Serbia had fallen apart. In early September, Serbian forces advanced into Bosnia. By then, the Serbian front was a sideshow, dwarfed by the clash of the Russian and Austro-Hungarian armies in Poland and Galicia.